This invention relates to an improvement in sterile syringe injection devices, in which a vial having an elastomeric sealing piston mounted therein is carried by an improved syringe connector, to provide sterile access to the contents of the vial for its transfer in sterile manner into a parenteral solution container, solution administration set, or the like, which has a projecting, resealable injection site.
Representative prior art structures which can be used for a similar purpose are disclosed in U.S. Pat. Nos. 2,371,086; 3,376,866; and 3,378,008. In each of these patents, as well as other patents and publications, a sterile vial is provided in conjunction with a syringe connector assembly having a hollow injection needle exposed at both ends. One end of the injection needle penetrates the closure of the vial, while the other end of the needle is used for injection.
This type of system finds particular use in the area of adding supplemental medication to parenteral solution containers. The supplemental medication, which may be potassium chloride solution or other medicament as required by a patient, can be added to a parenteral solution container, such as a VIAFLEX parenteral solution bag of the type sold by Travenol Laboratories, Inc., by penetrating the closure member of the parenteral solution container by one end of the injection needle, and then penetrating the vial of medicament with the other end of the needle, followed by slowly sliding an elastomeric sealing piston associated with the vial into the vial, to cause the medicament solution to be expelled through the injection needle.
However, the many designs of the cited prior art have several drawbacks.
First, in the prior art such as U.S. Pat. No. 3,378,008, when the rear end of the injection needle is forced through the elastomeric sealing piston of the vial, the needle may accidentally cut a small core of rubber from the sealing diaphragm of the sealing piston as it advances. This core may enter and remain in the bore of the needle, restricting or completely blocking the flow of the contents of the vial through the needle, or pass into the container into which an injection is being made.
Second, in similar prior art, the front needle ends of the prior art vial and syringe connector assemblies are inconveniently and dangerously exposed, to prick fingers during use, and to pick up contamination. Also, the needle can be advanced through the injection site in a direction not quite axial to it, which may cause the needle to penetrate a wall of plastic parenteral solution bag, which in turn may cause a leak and spoil sterility. In this event, both the parenteral solution bag, and the vial and syringe connector assembly, may have to be discarded and the whole preparation process begun again with new equipment.
However, when a needle has a protective sleeve, it has been found with respect to parenteral solution bags that many auxiliary medicament solutions ineffectively mix with the parenteral solution in a bag. This problem becomes more severe as the density of the medicament solution increases. For example, potassium chloride, due to its high density will often not mix satisfactorily with the parenteral solution unless the injection needle of the connector assembly can penetrate farther into the parenteral solution container (via the injection site) than is possible with a needle surrounded by a simple sleeve, of the type currently offered for sale.
In accordance with this invention, means are provided to eliminate these drawbacks, separately or in combination as desired.